This invention relates generally to a circuit arrangement for correcting horizontal pincushion distortion in a cathode ray tube drive circuit.
In a wide angle color cathode ray tube (CRT) used in a television set, video display terminal of a computer or the like, when the deflecting coils are designed so that misconvergence is minimum, then the shape of raster obtained on the screen of the CRT does not become a rectangle such that left and right side edges are arcuate inwardly so that so called horizontal pincushion distortion occurs.
In order to correct such horizontal pincushion distortion a correcting circuit is used in a conventional circuit arrangement. Although such conventional circuit arrangement is satisfactory as long as the vertical deflection frequency is constant, desired amount of correction of horizontal pincushion distortion cannot be obtained when the vertical deflection frequency varies.